Intracranial arachnoid cysts--do they impair mental functions?

OBJECT: Arachnoid cysts are benign, congenital malformations of the arachnoid with a predilection for the temporal fossa. Radiologically, most arachnoid cysts appear to be expansive lesions, and functional imaging has shown that arachnoid cysts may cause a reorganization of cortical functions.
METHODS: The present article is based on a literature search for articles reporting dyscognition or psychiatric symptoms in arachnoid cyst patients. Emphasis is placed on systematic, prospective studies reporting results from larger series of patients. A total of five articles were identified that had investigated cognition in larger series of patients. A variety of cognitive functions were found to be impaired, including verbal perception and memory, more complex verbal tasks, visuospatial functions, and visual attention. In addition, numerous case reports were identified that link arachnoid cysts to a wide variety of neuropsychiatric and cognitive symptoms.
CONCLUSIONS: This survey indicates that arachnoid cysts may affect cognition and also that they do so in a reversible manner, as the patients' cognitive impairment seems to improve after surgical decompression of the cyst.